Equilibrium

Example

The market for cookies is huge, with many consumers and many sellers.

The supply follows the equation `Q_S = 3 P`.

The demand follows the equation `Q_D = 10 - 2 P`.

In equilibrium, supply equals demand $$ \begin{align*} Q_S &= Q_D \\ 3 P &= 10 - 2 P \\ 5 P &= 10 \\ P &= 2 \end{align*} $$

In equilibrium, a banana is sold for $2 and there are 6 bananas on the market.

Question